> ## Documentation Index > Fetch the complete documentation index at: https://docs.arcuserp.com/llms.txt > Use this file to discover all available pages before exploring further. # List custom field definitions > Returns custom-field schema rows for the calling entity. Filter by `parent_type` to scope to a single resource type. Requires the `custom_fields:read` scope. ## OpenAPI ````yaml /openapi.yaml get /custom_fields openapi: 3.1.0 info: title: Arcus ERP Public API version: 1.0.0 description: > Arcus ERP public REST API. Designed for external integrations and data migration. **Authentication.** Bearer token (API key) via the `Authorization` header. Format: `Authorization: Bearer ark_live_ent__` (or `ark_test_*` for sandbox). API keys are issued per-entity in **Settings > Developers > API Keys**. **Entity scoping.** The entity is encoded in the API key prefix; routes are flat (e.g. `/v1/accounts`, `/v1/orders`, `/v1/products`). A small set of platform endpoints (migration, reconciliation, events, webhook endpoints, API keys) use the `/v1/entities/{entity_id}/...` form -- those are noted in their tags. **Key capabilities.** - Related-resource hydration via `?expand[]=` (see `x-arcus-expand` on each resource). - Cursor-based pagination (`starting_after` / `ending_before` / `limit`). - Idempotency via the `Idempotency-Key` header. - Webhook events for asynchronous notification. - Conditional requests / ETag for cache validation. servers: - url: https://api.arcuserp.com/v1 description: Arcus ERP API (accepts both live `ark_live_*` and test `ark_test_*` keys) - url: https://dev-api.arcuserp.com/v1 description: >- Dev sandbox API (test-only data, accepts `ark_test_*` keys against dev RDS) security: [] paths: /custom_fields: get: tags: - CustomFields summary: List custom field definitions description: | Returns custom-field schema rows for the calling entity. Filter by `parent_type` to scope to a single resource type. Requires the `custom_fields:read` scope. operationId: listCustomFieldsV1 parameters: - name: parent_type in: query required: false schema: type: string description: >- Restrict to a single parent resource type (account, product, order, ...). - name: is_active in: query required: false schema: type: boolean - $ref: '#/components/parameters/Limit' - $ref: '#/components/parameters/StartingAfter' responses: '200': description: CustomField list content: application/json: schema: type: object properties: object: type: string example: list data: type: array items: $ref: '#/components/schemas/CustomField' has_more: type: boolean security: - ApiKeyAuth: - custom_fields:read components: parameters: Limit: name: limit in: query required: false description: | Maximum number of records to return per page. Default 25, max 500. Use together with starting_after for cursor pagination. For larger bulk extraction workflows prefer the migration endpoints. schema: type: integer minimum: 1 maximum: 500 default: 25 StartingAfter: name: starting_after in: query required: false description: | Cursor for pagination. Pass the id of the last record from the previous page to fetch the next page. Mutually exclusive with ending_before. schema: type: string maxLength: 200 schemas: CustomField: type: object description: > A user-defined custom field attached to a parent resource type (`parent_type` is one of: account, product, order, vendor_bill, etc.). Values are stored separately in `entity_custom_field_values` and read/ written via the `/custom_fields/{parent_type}/{parent_id}/values` and `/custom_fields/{custom_field_id}/values/{parent_id}` endpoints. Scope: custom_fields:read / custom_fields:write / custom_fields:delete. properties: id: type: string format: uuid readOnly: true object: type: string example: custom_field entity_id: type: string format: uuid readOnly: true parent_type: type: string description: Parent resource type this field attaches to. 1..30 chars. example: account field_key: type: string description: >- Stable machine identifier. 1..80 chars. Unique per (entity, parent_type). example: tax_id_secondary label: type: string description: Human-readable label rendered in UI. 1..150 chars. example: Secondary Tax ID field_type: type: string enum: - text - number - date - datetime - boolean - json - select - multiselect description: >- Storage type. Drives which `value_*` column is written in entity_custom_field_values. example: text required: type: boolean default: false options: type: array nullable: true items: type: string description: For select / multiselect field_type only. default_value: type: string nullable: true help_text: type: string nullable: true display_order: type: integer default: 0 is_active: type: boolean default: true metadata: type: object description: Free-form caller metadata. Default {}. deleted_at: type: string format: date-time nullable: true readOnly: true description: Set by softDelete; cleared by restore. created_at: type: string format: date-time readOnly: true updated_at: type: string format: date-time readOnly: true securitySchemes: ApiKeyAuth: type: http scheme: bearer description: | API key issued per entity via Settings > Developers > API Keys. Each key carries scopes (e.g. orders:read, products:write). Bearer token format: Authorization: Bearer ark_live_ent__ Test keys use ark_test_ent__. Both are issued per entity via Settings > Developers > API Keys. ````